# Is it possible to have multiple inheritance?

**URL:** <https://alloytools.discourse.group/t/is-it-possible-to-have-multiple-inheritance/518>\
**Category:** Questions\
**Created:** [March 12, 2025, 6:02pm UTC](https://alloytools.discourse.group/t/is-it-possible-to-have-multiple-inheritance/518 "2025-03-12T18:02:22Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Alejandro](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Alejandro](https://alloytools.discourse.group/u/Alejandro)\
**Post date:** [March 12, 2025, 6:02pm UTC](https://alloytools.discourse.group/t/is-it-possible-to-have-multiple-inheritance/518/1 "2025-03-12T18:02:22Z")

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This may be a stupid question, but for the sake of completeness: can something like this be expressed?

```auto
sig C extends A, B {}

```

I’m not sure yet if this even can be useful at all, I’m just exploring alloy.

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**Author:** ![grayswandyr](https://yyz2.discourse-cdn.com/free1/user_avatar/alloytools.discourse.group/grayswandyr/32/17_2.png) [@grayswandyr](https://alloytools.discourse.group/u/grayswandyr)\
**Post date:** [March 12, 2025, 9:09pm UTC](https://alloytools.discourse.group/t/is-it-possible-to-have-multiple-inheritance/518/2 "2025-03-12T21:09:25Z")

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A signature may only extend one signature, but extension can completely be mimicked using `in` and additional `fact`s. So, yes, you can use multiple inheritance with a bit of work.